diff --git a/VM/src/lobject.h b/VM/src/lobject.h
index a3864ce9..70a51923 100644
--- a/VM/src/lobject.h
+++ b/VM/src/lobject.h
@@ -84,7 +84,6 @@ typedef struct lua_TValue
 
 // Internal tags used by the VM
 #define LU_TAG_ITERATOR LUA_UTAG_LIMIT
-#define LU_TAG_COUNT (LU_TAG_ITERATOR+1)
 
 /*
 ** for internal debug only
diff --git a/VM/src/lstate.h b/VM/src/lstate.h
index 967418ab..808f57b9 100644
--- a/VM/src/lstate.h
+++ b/VM/src/lstate.h
@@ -197,7 +197,7 @@ typedef struct global_State
     struct Table* mt[LUA_T_COUNT];                   // metatables for basic types
     TString* ttname[LUA_T_COUNT];       // names for basic types
     TString* tmname[TM_N];             // array with tag-method names
-    TString* lightuserdataname[LU_TAG_COUNT]; // names for tagged lightuserdata
+    TString* lightuserdataname[LUA_LUTAG_LIMIT]; // names for tagged lightuserdata
 
     TValue pseudotemp; // storage for temporary values used in pseudo2addr
 
diff --git a/VM/src/ltm.cpp b/VM/src/ltm.cpp
index a1838b6a..09c3d824 100644
--- a/VM/src/ltm.cpp
+++ b/VM/src/ltm.cpp
@@ -131,10 +131,15 @@ const TString* luaT_objtypenamestr(lua_State* L, const TValue* o)
     }
     else if (ttislightuserdata(o))
     {
-        const TString* name = L->global->lightuserdataname[lightuserdatatag(o)];
+        int tag = lightuserdatatag(o);
 
-        if (name)
-            return name;
+        if (unsigned(tag) < LUA_LUTAG_LIMIT)
+        {
+            const TString* name = L->global->lightuserdataname[tag];
+
+            if (name)
+                return name;
+        }
     }
     else if (Table* mt = L->global->mt[ttype(o)])
     {